Efficacy and safety of SY-3505, a third-generation ALK TKI, in <i>ALK</i>-positive advanced non-small cell lung cancer: Results from a phase I/II, multi-center study.
Authors: Yuankai Shi, Xingsheng Hu, Xingya Li, Yongsheng Li, Ke Wang, Pingli Wang, Liyan Jiang, Shucai Zhang, Xiangjiao Meng, Huijuan Wang, Xiaorong Dong, Runxiang Yang, Yongzhong Luo, Qi Mei, Yinghui Sun
Journal: Journal of Clinical Oncology (2023)

9110 Background: SY-3505 is a potent, brain-penetrant, 3 rd -generation (gen) anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI) with preclinical activity against both wild-type and most known resistance mutations of ALK occurring in 1 st and 2 nd -gen ALK TKI-resistant patients. Here we report the efficacy and safety results from the ongoing phase I/II study of SY-3505. Methods: Patients aged ≥18 years with histologically/cytologically confirmed, advanced, ALK-positive non-small cell lung cancer (NSCLC) and an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-2 were recruited from 13 hospitals in China. In phase I study, patients received SY-3505 from 25-800mg once daily in dose-escalation phase, followed by dose-expansion at 500/600mg. Patients received alectinib only or ≥2 prior ALK TKIs were recruited in phase II study and treated with SY-3505 at 600mg once daily. The primary endpoint was investigator (INV)-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Secondary endpoints included disease control rate (DCR), duration of response (DoR), progression-free survival (PFS), overall survival (OS) and safety. Results: At data cut-off date of Feb.03, 2023, 92 ALK-positive NSCLC patients were enrolled in phase I/II, 82 were evaluable for efficacy, the ORR was 34.2% (95% confidence interval [CI] 24.0-45.5%), DCR was 74.4% (95% CI 63.6-83.4%). Herein the ORR and DCR of 59 patients in phase I for dose-escalation and dose-expansion was 32.3% (95% CI 20.6-45.6%) and 69.5% (95% CI 56.1-80.8%), respectively; median DoR and PFS was 11.1 (95% CI 5.28-not reached [NR]) and 6.20 (95% CI 3.08-10.3) months, respectively. Fifty-six patients received SY-3505 at 600mg once daily (two patients received non-alectinib 2 nd -gen ALK TKI only, 22 received alectinib only and 32 received ≥2 prior ALK TKIs). Thirty-two (57.1%) patients experienced treatment-related adverse events (TRAEs) and two (3.6%) had grade ≥3 TRAEs. The most common TRAEs were diarrhea (42.9%), nausea (28.6%) and vomiting (26.8%), consistent with previous reported in phase I. Forty-seven patients were evaluable for efficacy, the ORR and DCR was 38.3% (95% CI 24.5-53.6%) and 83.0% (95% CI 69.2-92.4%), respectively. Median DoR and PFS were NR. Twenty-two patients had baseline central nervous system metastases, the ORR and DCR was 50.0% and 86.4%, respectively. Conclusions: SY-3505 was well-tolerated and showed significant and durable clinical activity in ALK-positive NSCLC patients who received at least one prior 2 nd -gen ALK TKI, demonstrating a potential new treatment option for these patient population. Pivotal clinical study will be performed in future. Clinical trial information: NCT05257512 .